I'm going to fit EFI to my S1 XJ6 and have a possible solution to the EFI fuel system requirements. I know that a high pressure fuel system needs a return circuit and that if I fitted S3 Fuel Tanks it would provide a known solution, but I am deterred by the possibility of having issues when removing the old tanks and the cost of replacements.

To this end, I am considering the following:

- Install a 2-3Ltr Surge Tank together with a 044 Bosch Fuel Pump.
- Install a return line from engine bay to Surge Tank.
- Utilise the standard Carb fuel Pumps to feed the Surge Tank.
- Fit an overflow line from the Surge Tank to Original Tanks via the Fuel Sender Unit.

Obviously I would have to include some additional shut off valves to maintain independent tank use, but I think it would work well and have the capacity for increased performance in the future.

Do you think the Carb Fuel Pumps will be up to the task of supplying the surge tank with enough fuel?

 

ED-3605 Universal Fuel Reservoir Kit might work for your use with EFI. On my '71 S1 383/200R I plan to use this tank when converting to their EFI on my V8. Will make a one day very clean install for my car!

Even though I changed out my '72 S1 tanks with S2 tanks with return lines - that is a lot of work and expense. I used a Pollak (6) port valve system with
ports for two return lines to allow fuel to be properly returned this new tank
will be much easier and as cheap or cheaper...plus not running new fuel lines
and hoses and adding an inline pump will help.

 

Roger, that's quite a novel solution, but I'm happy to install a return fuel line. I know I can get a genuine 044 Bosch Fuel Pump for $200 and that is good for over 500bhp. A 2.5ltr Surge Tank, Pump Bracket and all associated fittings can be had for $200 and another $100 for fuel lines, relay and wire.

I guess I just wanted to know if the low pressure flow rate of the standard Fuel Pumps would be enough to keep the Surge Tank supplied with fuel. My initial guess is that they would be fine.

 

I reckon you will be fine with that system.

Those carby pumps are high flow, and low pressure, and the carby pumps on the 6cyl and V12 are the same part number in the XJ sedans. The V12's had 4 carbies and loved the fuel, and also had a return line.

As you probably already know, most of the fuel supplied up front on an EFI car is returned to the tank, supposedly to keep the fuel cool??, dunno.

 

It is priced a little high, but the advantages outweigh the price = ease of
install and "pro designed system"...plus it will fit in the XJ engine
compartment and look "proper". Just be sure the output pressure is good for
your installation - I am using their system so no problems...

Just run the current feed line from your pump(s) to the surge tank
and the fuel line from the tank to your EFI...no Bosch anything (that
is good in my opinion). Bosch and Lucas are the two worst words in the
English language....